This invention relates generally to a camera, and more particularly to a camera of the type using film that is accommodated in a removable cassette.
Still more specifically, the invention relates to such a camera which includes electrically energizable components.
It is already known to provide cameras with built-in electronic flash devices having a flash circuit for firing the flash tube of the device. Cameras of this type have obvious advantages in terms of ease of operation, elimination of any need for separate flash bulbs, and the like. They are, however, rather large, due to the incorporation of the flash circuit and the power source --e.g. dry cells, rechargeable cells-- needed to power this circuit. This makes such cameras much less portable than is desired.
However, this type of arrangement is known for 35 mm cameras and others using similar small film, that is cameras where the question of small size and light weight is of very considerable importance. This is a consideration which is of minor importance in the type of camera which uses self-developing film, of which the "Polaroid" cameras are an example. Because these cameras use film which, when exposed, develops directly within or immediately outside the camera, this film must have a size corresponding to that of the finished picture. This, in turn, means that the film cannot be small, and neither can the cassette be small in which it is supplied.
Therefore, the incorporation of electrically powered circuits in such a camera represents no particular problem, since the camera must be large to be able to operate with the large film, and the incorporation of the circuits will not add too much to the overall size and weight of such a camera.
There is, however, a problem with the electric energy for the circuit or circuits. The use of dry cells is preferred, because these are less expensive than the much more costly rechargeable cells. Dry cells, however, have some disadvantages. There are some types which tend to develop leaks, leading to corrosion of various camera components. Then, again, dry cells have a limited shelf life, which means that when they are left in a camera for some time the user may, on trying to operate the camera, find that the dry cells are no longer operative. Also, when the dry cells are left in the camera, even when the latter is not in use, there is always the possibility that the circuits powered by them might be accidentally triggered, resulting in the waste of at least one film negative.